Method of relaying space-telegraph signals.



No. 717,5!0. Patented Dec. 30, I902.

' J. S. STONE;

METHOD OF RELAYING SPACE TELEGRAPH SIGNALS.

(Application filed Jan. 23, 1901.)

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TRUSTEES.

METHOD OF RELAYING SPACE-TELEGRAPH SIGNALS.

SPECIFICATION forming part of Letters Patent N0. 717,510, dated December 30, 1902.

Application filed January 28, 1901. Serial No. 44,388. (No model.)

To all whom it may concern:

Be it known that I, J .OHN STONE STONE, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Methods of Relaying Space-Telegraph Signals, of which the follow-.

ing is a specification.

The invention relates to the art of signaling electrically between stationsnot connected by a conducting-wire, sometimes called space telegraphy, and more particularly to the type of space telegraphy in which the signals are transmitted by unguided electromagnetic waves. The distance to which itis at present practicable to signalby means of unguided electromagnetic waves is limited to distances considerably less than those usually communicated over by the ordinary telegraph and telephone of today. It is of the greatest importance,therefore,that suitable methods and means for automatically relaying space-telegraph signals be discovered and devised. So

far as I am aware no method or means for automatically relaying space-telegraph sig nals has heretofore been disclosed except such as depend for such elficiency as they may possess upon the use of a metallic screen as a material shield or barrier against the passage of the electromagnetic waves. Without considering in this connection the practical efficiency of such means it seems sufficient to point out that the present invention does not involve the idea of any material shield or barrier, but rather an electrical organization of the apparatus whereby the desired result may be obtained.

The object of the present invention is to provide a method whereby space-telegraph messages may be automatically relayed. This object I attain by receiving from the transmitting-station of a space-telegraph system the electromagnetic waves to be relayed in a suitable receiving device and by so associating with this receiving device a telegraphic relay operating the transmitting device of a second space-telegraph system that the signals emitted therefrom shall affect the receivingstation of said second system, but not the receiving device of the first system.

In a specific embodiment of the invention I employ a space-telegraph system comprising a transmitter and a receiver, the electromagnetic waves of which transmitter are in whole or in part of asimple harmonic character and of a fixed or predetermined frequency. These signal-waves are received by a receiver which is tuned to respond only to signalwaves of the frequency of those emitted by the said transmitter and which operates a relay which when set in motion in turn operates thetransmitter of a second space-telegraph system, which-transmitter is so tuned as to develop and transmit simple harmonic electromagnet signal-waves of a different frequency from those emitted by the first transmitter. The electromagnetic signal-waves so transmitted are received in practice at a receiver-station, which in turn may be tuned to respond only to the signal-waves of the particular frequency developed by the said second transmitter.

In an application filed by me February 8, 1900,SerialNo.4,505,andsubsequentllydivided a method and apparatus for tuning a transmitter so that it will transmit electromagnetic waves of but a single fixed frequency and in like manner tuning a receiver so that it will receive only electromagnetic signalwaves of a single fixed frequency are described and claimed, and the method and apparatus therein described are made use of in this specification to illustrate the present invention; butit is to be definitely understood that the present invention is not limited to such method or apparatus.

Inthe figures, at represents a generator of vibratory currents of moderate frequency. 70 is a key. R is a relay. T is an electric translating device. It is a contact normally open, but closed by the relay B. Fig. 2, when the latteris set in motion. M, M, M, and 1V are induction-coils or transformers. S is a spark-gap. C, O, C", O' are condensers. L

L L are inductance-coils. V and V are vertically-elevated conductors. E is an earth connection. K is a coherer, and Bis a battery.

Figure 1 represents a transmitter so tuned that it will transmit electromagnetic signalwaves of practically but a single fixed frequency. Fig. 2 represents a receiver tuned to the same frequency as that of the transmitter of Fig. land alsoin association therewith a second transmitter tuned to a different frequency. A relay R is so arranged as to I be set in motion by the signals received at this receiver and when so set in motion to cause the said second transmitter to transmit corresponding signals to the receiver shown at Fig. 3. This receiver is preferably, though not necessarily,tuned to the same frequency as that of the second transmitter with which it is associated.

By means of the three apparatus shown in the drawings an operator at the transmitter shown in Fig. 1 may communicate with a second operator at the receiver shown in Fig. 3 through the intermediary of the apparatus shown in Fig. 2 even when the receiver shown at Fig. 3 is too remote from the transmitter shown at Fig. l for such communica tion to take place directly without relaying.

The construction and mode of operation of the transmitters and receivers shown in the drawings are described at length in the hereinbefore-mentioned application and need not, therefore, be further described here. Suffice it to say that when the operator at the transmitter shown at Fig. 1 depresses the key approximately simple harmonic electromagnetic waves of a fixed periodicity emanate.

from the vertical wire V of that station. These waves impinging upon the vertical wire V of the receiver depicted at Fig. 2 develop therein electric vibrations of a corresponding frequency, and the energy of these vibrations is conveyed, through the intermediary of the induction-coil M, to a resonant electric circuit 0 O L, attuned to the same frequency as that of the said vibrations. By virtue of this resonance a high electromotive force is developed at the terminals of the condenser O", and this electromotive force operates the coherer K, which sets in motion the relay R. This in turn causes the closure of the circuit of the generator at at the contact-point 7c. The closure of this circuit results in the production of a vibratory current in the resonant circuit S C L, which is approximately simple,harn1onic in character, and of a different frequency from that to which the circuit 0 C L is attuned. The energy of these vibrations is conveyed, through the intermediary of the inductioncoil M, to a second resonant circuit C L, whichis attuned to the same frequency as the circuit S O L and which tends to suppress any harmonics which may be contained in the vibrations developed in the circuit S O L.

The energy of the vibrations in the circuit C L is conveyed, through the intermediary of the induction-coil M, to the elevated conductor V, in which are thereby developed simple harmonic vibrations of the frequency to which the circuits S O L and O L are attuned. As a result of these electric vibrations in the vertical wire V electromagnetic waves of a frequency corresponding to that of the vibrations are emitted from the vertical wireV,and these latter waves impinging upon the vertical wire V of the receiver shown at Fig. 3 cause the electric translating device T of that station to be set in motion in a manner fully set forth in the application hereinbefore mentioned.

For the purpose of sending a series of signals a decoherer (not shown in the drawings) may be employed to restore the coherer. (Shown at K in Fig. 2 and Fig. 3.) The electromagnetic waves emanating from the vertical wire V, Fig. 2, do not affect the receiver device of that figure, because they are of a different frequency from that to which the resonant circuit 0 O L is attuned. Except the vertical wires V V, Fig. 2, be separated by a considerable distance by an extension of the circuit connecting 70 with ct it may be found necessary to interpose more than one resonant circuit between the vertical wire V, Fig. 2, and the coherer K, and, similarly, it may be found necessary to interpose several resonant circuits between the spark-gap S, Fig. 2, and the vertical wire V. The manner in which this may be accomplished is fully described in the hereinbeforementioned two applications.

In two other applications filed by me contemporaneously herewith, Serial Nos. 414,387 and 44,396, I have shown and described another method and other apparatus for so associating the receiver of one. space-telegraph system with the transmitter'of another that the latter shall not affect the former. It will be perceived, however, upon careful consideration that the two forms of apparatus shown in my two said applications and the particular form shown herein all owe their efficiency to the fact that in them all the main system and the relay-operated system are so associated that the transmitter of the relay system, while affecting the receiver of that system, does not affect the receiver of the main system. It follows in like manner that all three forms of apparatus (the one herein described and the two disclosed in my applications aforesaid) embody methods of operation which are species of a common or ge-' neric method of relaying in space telegraphy, of which I believe myself to be the original and first inventor and which is therefore hereinafter broadly claimed.

I claim-- 1. The method of relaying signals received by the receiver of a space-telegraph system, which consists in so electrically organizing and associating therewith the transmitter of tern, which consists in causing such signals to a second space-telegraph system, operated by affect the sending of similar signals by waves ID a relay set in motion by the receiver of the of a different frequency.

first, that the said transmitter while affecting the receiver of the second system, will not JOHN STONE STONE affect the receiver of the first. In presence of i 2. The method of relaying signals received ALEX. P. BROWNE,

by a tuned receiver of a space-telegraph sys- ELLEN B. TOMLINSON. 

